Process for the preparation of diketopyrrolopyrroles

ABSTRACT

The present invention relates to a process for the preparation of diketopyrrolopyrroles of the formula (I), wherein A1, A2, A3 and A4 are as defined in the description of the present invention, to new diketopyrrolopyrroles of the general formula I obtainable by the process, and the use of the new diketopyrrolopyrroles of the general formula I for the preparation of inks, colorants, pigmented plastics for coatings, non-impact-printing material, color filters, cosmetics, polymeric ink particles, toners, dye lasers and electroluminescent devices, or as fluorescent markers for immunoassays and fluorescent tracers for leak detection of fluids. Furthermore the present invention relates to diketopyrrolopyrrole analogues of the general formula (II), wherein A1, A2 and A3 are defined in the description of the present invention, which are intermediates in the process for the preparation of diketopyrrolopyrroles of the formula I and can be used as crystal growth regulators

The present invention relates to a process for the preparation ofdiketopyrrolopyrroles (“DPPs”) of the formula I, to newdiketopyrrolopyrroles of the general formula I obtainable by theprocess, and the use of the new diketopyrrolopyrroles of the generalformula I for the preparation of inks, colorants, pigmented plastics forcoatings, non-impact-printing material, color filters, cosmetics,polymeric ink particles, toners, dye lasers and electroluminescentdevices, or as fluorescent markers for immunoassays and fluorescenttracers for leak detection of fluids.

Furthermore the present invention relates to diketopyrrolopyrroleanalogues of the general formula II, which are intermediates in theprocess for the preparation of diketopyrrolopyrroles of the formula Iand can be used as crystal growth regulators.

DPP Compounds of the formula

are known:

Compounds of the formula X in which Y¹ and Y² denote hydrogen and Y³ andY⁴ denote identical or different isocyclic or heterocyclic aromaticradicals are known as red pigments from EP-B-61,426.

U.S. Pat. No. 5,973,146 relates to aminated diketobis(aryl orheteroaryl)pyrrolo-pyrroles and their use as photoconductive substances.

EP-A-1 087005 relates to fluorescent diketopyrrolopyrroles of theformula I′

wherein R₁′ and R₂′, independently from each other, stand forC₁-C₂₅-alkyl, allyl which can be substituted one to three times withC₁-C₃alkyl or Ar₃′, —CR₃′R₄′—(CH₂)_(m)′—Ar₃′, wherein R₃′ and R₄′independently from each other stand for hydrogen or C₁-C₄alkyl, orphenyl which can be substituted one to three times with C₁-C₃ alkyl,Ar₃′ stands for phenyl or 1- or 2-naphthyl which can be substituted oneto three times with C₁-C₈alkyl, C₁-C₈alkoxy, halogen or phenyl, whichcan be substituted with C₁-C₈alkyl or C₁-C₈alkoxy one to three times,and m′ stands for 0, 1, 2, 3 or 4, and wherein C₁-C₂₅alkyl or—CR₃′R₄′—(CH₂)_(m′)—Ar₃, can be substituted with a functional groupcapable of increasing the solubility in water such as a tertiary aminogroup, —SO₃ ⁻, or PO₄ ²⁻, Ar₁′ and Ar₂′, independently from each other,stand for an aryl or heteroaryl group. The DPP compounds can be used forthe preparation of inks, colorants, pigmented plastics for coatings,non-impact-printing material, color filters, cosmetics, or for thepreparation of polymeric ink particles, toners, dye lasers andelectroluminescent devices. EP-A-1087006 describes electroluminescentdevices comprising the DPP compounds of formula (I′). The DPPsexemplified in EP-A-1087005 and EP-A-1087006 are symmetricallysubstituted at the nitrogen atoms of the DPP basic unit.

EP-A-499 011 discloses organic electroluminescent elements, comprising acompound of formula X wherein Y³ and Y⁴ are independently of each othera 3-pyridyl or 4-pyridyl residue or a substituted or unsubstitutedphenyl group and Y¹ and Y² are independently of each other hydrogen,C₁-C₁₈alkyl, C₃-C₁₈-alkenyl or a phenylalkyl group having 1 to 5 carbonatoms in the alkyl. The exemplified DPPs,2,5-dihydro-2,5-dimethyl-3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4-dione and2,5-dihydro-2,5-dimethyl-3,6-di(2′-methoxyphenyl)pyrrolo[3,4-c]pyrrole-1,4-dione(example 8 and 10, respectively), are symmetrically substituted at thenitrogen atoms of the DPP basic unit.

WO 98/33862 describes the use of a DPP-compound of formula

as a guest molecule in electroluminescent devices [example B2].

EP-A-811 625 discloses DPP compounds of the formula

wherein Y¹¹ is a quinacridone or DPP radical.

WO96/08537 relates to a process for preparing N-methylated organicpigments.

EP-A-467 846 relates to electrochromic compositions containing at leastone DPP derivative.

The DPP derivatives are symmetrically substituted at the nitrogen atomsof the DPP basic unit or one nitrogen atom is substituted by hydrogenand the other nitrogen is substituted by a group (CH₂)_(p)-L, wherein pis an integer of 1 to 6 and L is a sulfonic acid, a phosphonic acid, acarboxylic acid group or a salt thereof, or an ammonium group.

WO98/25927 relates to liquid crystalline diketopyrrolopyrroles, whichare symmetrically substituted at the nitrogen atoms of the DPP basicunit.

The compounds of the above-mentioned general formula X can be preparedby various known processes:

According to the process described in EP-B-61,426, a nitrile of theformula Y³—CN is reacted, if desired together with a nitrile of theformula Y⁴—CN, with bromoacetic ester and zinc, a compound of theabove-mentioned formula where Y¹═Y²═H being formed. Better yields areobtained if 2 mol of the nitrile Y³—CN or the nitrile mixtureY³—CN/Y⁴—CN are reacted in a manner known per se with 1 mol of a diethylsuccinate in an organic solvent in the presence of a strong base atelevated temperature, cf. EP-B-94,911.

U.S. Pat. No. 4,585,878 relates to N-subsbtuted1,4-diketopyrrolo[3,4-c]pyrroles of the above-mentioned general formulain which Y³ and Y⁴ are isocyclic aromatic or heterocyclic aromaticradicals, in particular unsubstituted or substituted phenyl or naphthyl,and Y¹ and Y² are independently of one another alkyl, alkoxycarbonyl,phenyl, benzoyl or benzyl, which are suitable for dyeing high molecularweight organic material.

The compounds of the above-mentioned formula are prepared

-   (a) by reacting the compound of the formula

with a compound containing the radicals Y¹ and/or Y² as leaving groups,in an organic solvent, or

-   (b) by reacting 2 moles of a compound of the formula

or one mole each of the compounds of the formulae (XI) and (XII), with 1mole of a succinic acid diester in the presence of a base and an organicsolvent (cf. J. Chem. Soc. 1976, page 5) and then dehydrogenating theproduct. The exemplified DPPs, for example2,5-dihydro-2,5-dibenzyl-3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4-dione and2,5-dihydro-2,5-bis(4′-chlorophenyl-3,6-di(4′-chlorophenylpyrrolo[3,4c]pyrrole-1,4-dione(example 8 and 10, respectively), are symmetrically substituted at thenitrogen atoms of the DPP basic unit. U.S. Pat. No. 5,354,869 relates to3,6-bis-(2′-methoxyphenyl)-2,5-dihydro-2,5-dimethyl-pyrrolo[3,4-C]pyrrole-1,4-dioneand its use as storage media in optical memories. Described is also aprocess for the preparation of the compounds of the general formula Xwhich consists in reacting furanofurandione of the general formula

with a primary amine of the general formula Y¹NH₂ or with a mixture ofprimary amines Y¹NH₂/Y²NH₂ wherein Y¹, Y², Y³ and Y⁴ denote hydrogen,aromatic radicals, heteroaromatic radicals, heterocyclic radicals orother non-water-solubilising radicals. The exemplified DPPs, for example2,5-dihydro-2,5-diphenyl-3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4-dione and2,5-dihydro-2,5-bis(4′-methylphenyl-3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4-dione(example 13 and 14, respectively), are symmetrically substituted at thenitrogen atoms of the DPP basic unit. In Liebigs Ann. 1996, 679-682H.Langhals et al. disclose the synthesis of N-arylpyrrolopyrrolediones.

Condensation of 1 with aniline yields the intermediate 2 [yield: 15.6%]as an orange powder with a weak yellow solid state fluorescence. Theintermediate 2 was condensed with para-t-butylaniline yielding theunsymmetric substituted dye 3 [yield: 2.5%]. The overall yield of thedisclosed synthesis is very low.

In view of the above-mentioned state of the art it is the object of thepresent invention to provide a new process for the preparation ofdiketopyrrolopyrroles which in particular make it possible to obtainDPPs which are unsymmetrically substituted at the nitrogen atoms of theDPP basic unit in an acceptable yield.

This object has surprisingly been solved by a process for thepreparation of diketopyrrolopyrroles of the general formula

comprising reacting a compound of the formula

with a primary amine of the formula A⁴-NH₂ (III),wherein A¹ and A² are C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkynyl,C₅-C-cycloalkyl, C₅-C₈cycloalkenyl, aryl or heteroaryl,

-   A³ is hydrogen, C₁-C₁₈alkyl, cyanomethyl, Ar³,    —CR³⁰R³¹—(CH₂)_(m)—Ar³ or Y-R₃₂,wherein R₃₀ and R³¹ independently of    each other stand for hydrogen or C₁-C₄alkyl, or phenyl which can be    substituted up to three times with C₁-C₃alkyl,-   Ar³ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or    heteroaryl, which can be substituted one to three times with    C₁-C₈alkyl, C₁-C₈alkoxy, halogen or phenyl, which can be substituted    with C₁-C₈alkyl or C₁-C₈alkoxy one to three times, and m stands for    0, 1, 2, 3 or 4, Y is —C(O)—, —C(O)O—, —C(O)NH— or —SO₂—, —SO₂NH—    and R³² is C₁-C₁₈alkyl, C₁-C₁₈alkoxy, —NH—C₁-C₁₈alkyl, Ar³, or    aralkyl,-   and A⁴ is C₁-C₁₆alkyl or Ar³.

The reaction between the compound of the general formula II and theprimary amine or the mixture of primary amines is carried out in asuitable inert solvent or dispersant. Suitable solvents or dispersantsare, for example, ethers, in particular those having 2 to 8 carbon atomsin the molecule, such as, for example, diethyl ether, methyl ethylether, di-n-propyl ether, diisopropyl ether, methyl n-butyl ether,methyl tert-butyl ether, ethyl n-propyl ether, di-n-butyl ether,tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, bis-B-methoxyethylether; oligoethylene glycol dimethyl ethers, such as, for example,pentaglyme; aliphatic hydrocarbons, such as, for example, hexane,heptane, low- and high-boiling petroleum ethers; cycloaliphatichydrocarbons, such as, for example, cyclohexane, methylcyclohexane,tetralin, decalin; aromatic hydrocarbons, such as, for example, benzene,toluene, o-, m- and p-xylene, ethylbenzene; halogenated aliphatic oraromatic hydrocarbons, such as, for example, methylene chloride,chloroform, carbon tetrachloride, chlorobenzene, dichlorobenzene;nitriles, such as, for example, acetonitrile; amides, such as, forexample, dimethylformamide, dimethylacetamide, N-methylpyrrolidone;hexamethylphosphoric triamide; and sulfoxides, such as, for example,dimethyl sulfoxide. Mixtures of various solvents can also be used.

The reaction is preferably carried out in a dipolar or non-polar aproticsolvent. Examples of preferred aprotic solvents are: dimethylformamide,dimethyl sulfoxide, hexamethylphosphoric triamide, sulfolane,N-methylpyrrolidone, tetramethylurea, acetonitrile, ethylene glycoldimethyl ether, ethylene glycol diethyl ether, diethylene glycoldimethyl ether and triethylene glycol dimethyl ether, nitromethane,1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU),1,3-dimethyl-2-imidazolidinone, benzonitrile, nitrobenzene, chloroform,carbon tetrachloride and methylene chloride. Particularly preferredaprotic solvents are chloroform, carbon tetrachloride and methylenechloride, of which chloroform is particularly preferred. The reactionbetween the compound of the general formula II and the primary amine IIIis carried out in the presence of a dehydrating agent. Examples ofsuitable dehydrating or water-eliminating agents of this type are:N,N′-disubstituted carbodiimides, in particular if they contain at leastone secondary or tertiary alkyl radical, such as, for example,diisopropyl-, dicyclohexyl- or N-methyl-N′-tert.-butylcarbodiimide (cf.“The Chemistry of Ketenes, Allenes and Related Compounds”, Part 2,Editor: S. Patai, John Wiley & Sons 1980, 722-753).Dicyclohexylcarbodiimide is particularly suitable.

The reaction between the compound of the formula II and the primaryamine III can be carried out, for example, at temperatures from −10° C.up to the boiling point of the solvent or solvent mixture used. In manycases it is carried out at −10 to 30° C. and preferably at roomtemperature. 0.9 to 1.4 mol, preferably 1.0 to 1.3 mol of the primaryamine III are in general employed per mole of compound of the generalformula II. The reaction can be catalyzed by adding a strong non-aqueousacid such as trifluoroacetic acid.

The primary amines III are known or can be easily prepared by themethods known for the preparation of these class of compound.

The starting compound of the formula II, wherein A³ is different from ahydrogen atom, is obtained by reacting a compound of the formula

with a compound of the formula A³-X (V), wherein A¹, A² and A³ have themeanings as given above and X is a leaving group. The reaction betweenthe compound of the general formula IV and the compound of the formula Vis carried out in a suitable inert solvent or dispersant such astetrahydrofuran or diethyl ether, in the presence of a base such assodium hydride at a temperature ranging from 20° C. to the boiling pointof the solvent. The term “eaving group” means a group, such as iodine,bromine or chlorine, benzene- or p-toluenesulfonate. Processes for theintroduction of A³ into compounds of the formula IV are described, forexample, in U.S. Pat. No. 4,585,878.

Suitable alkylating agents are, for example, alkyl halides, inparticular alkyl iodides, alkyl esters, in particular alkyl esters ofsulfonic acids, such as, for example, alkyl esters of benzene- orp-toluenesulfonic acid. Suitable arylating agents are for exampleiodoaryl compounds such as iodobenzene.

The starting compound of the formula IV is obtained by heating acompound of the formula

in an inert solvent,wherein A¹ and A² have the meanings as given above and R is C₁-C₁₈alkyl,in particular C₁-C₄alkyl, aryl, in particular phenyl, or aralkyl, inparticular benzyl, which can be substituted one to three times withC₁-C₈alkyl, C₁-C₈alkoxy, or halogen. Examples of inert solvents include,but are not limited to aromatic solvents, like biphenyl, para-, meta orortho-terphenyl, dibenzyltoluene, α-methyl- or β-methylnaphthalene,cyclic carbonates, like 1,3-dioxolan-2-one, ketones, like acetophenoneor benzophenone, γ-butyrolactone and ethylene glycols, likePhe-Cellosolve or Bu-Cellosove, or mixtures thereof, in particularmixtures of di- and triarylethers (Dowtherm A®). In a preferredembodiment the compound of the formula VI is dissolved in Dowtherm A®and heated for about 0.5 to 240 hours at a temperature of 220 to 260°C., preferably 230-240° C.

The present invention is also directed to the compounds of the formulaVI which are novel intermediates in the synthesis of thediketopyrrolopyrroles of the formula I and the diketopyrrolopyrroleanalogues of the formula II, respectively.

The starting compound of the formula VI is obtained by reacting acompound of the formula

with an ester of the formula A²-CO₂R (VIII) in the presence of a base,such as for example sodium tert.-amylate/tert.-amylalcohol at atemperature ranging from 25° C. to the boiling point of the solvent,wherein R, A¹ and A² have the meanings as given above.

The starting compounds of the formula VII are known or can be preparedin analogy to processes described in U.S. Pat. No. 4,681,971, U.S. Pat.No. 4,749,795, U.S. Pat. No. 4,720,305 and U.S. Pat. No. 4,659,775.

Alternatively, compounds of the formula

wherein A³ is different from a hydrogen atom and is in particular aryl,can be prepared by a copper catalyzed decomposition of diazoacetates inthe presence of enaminoamides (G. Maas, A. Müller, J. prakt. Chem. 340(1998) 315-322):

The compounds of the formula VII, wherein A³ is different from ahydrogen atom and is in particular aryl, can be reacted to compounds ofthe formula I as described above.

Furthermore, the present invention relates to noveldiketopyrrolopyrroles of the general Formula

wherein A¹, A² and A³ have the meanings as given above and A⁴ is Ar³,wherein preferably A⁴ is different from A³.

The DPPs of the general formula I show a high heat stability, a goodsolubility in polymers, hydrocarbon based fuels, lubricants, and water,a high light stability, and the ability to be used in plastics,especially polyamides, without decomposition and loss of lightfastness,and in paints; and can show photo- and electroluminescence as well assolid state fluorescence. The residues A¹ and A² are in general selectedfrom C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkynyl, C₅-C₈cycloalkyl, such ascyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl, in particularcyclohexyl, C₅-C₈cycloalkenyl, such as cyclopentenyl, cyclopentadienyland cyclohexenyl, in particular cyclohex-3-enyl, aryl and heteroaryl.

Diketopyrrolopyrroles, wherein A¹ and A² are radicals of the formula

R¹ and R² are independently of each other hydrogen, halogen,C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈alkylmercapto, di(C₁-C₁₈alkyl)amino,C₁-C₁₈alkylamino, C₁-C₈alkoxycarbonyl, C₁-C₁₈alkylaminocarbonyl, —CN,—NO₂, trifluoromethyl, C₅-C₈cycloalkyl, —C═N—(C₁-C₁₈alkyl), phenyl,

imidazolyl, pyrrazolyl, triazolyl, piperazinyl, pyrrolyl, oxazolyl,benzoxazolyl, benzothiazolyl, benzimidazolyl, morpholinyl, piperidinylor pyrrolidinyl, 13 CONX⁵X⁶, —C(O)OX⁷ or —SO₂X⁹; wherein X⁵ and X⁶ arehydrogen, linear or branched C₁₋₁₀-alkyl, C₅₋₁₀-cycloalkyl orC₆₋₁₀-aryl, X⁷ is hydrogen, linear or branched C₁₋₁₀-alkyl,C₅₋₁₀-cycloalkyl or C₆₋₁₀-aryl, X⁹ is hydrogen, linear or branchedC₁₋₁₀-alkyl, C₅₋₁₀-cycloalkyl, C₇₋₁₀-aralkyl, C₆₋₁₀-aryl or —NX¹⁰X¹¹,wherein X¹⁰ and X¹¹ are hydrogen, linear or branched C₁₋₁₀-alkyl,C₇₋₁₀-aralkyl or C₆₋₁₀-aryl,

-   G is —CH₂—, —CH(CH₃)—, —C(CH₃)₂—, —CH═N—, —N═N—, —O—, —S—, —SO₂—,    —CONH— or —NR⁷—, R³ and R⁴ are independently of each other hydrogen,    halogen, C₁-C₆alkyl, C₁-C₁₈alkoxy or —CN, R⁵ and R⁶ are    independently of each other hydrogen, halogen or C₁-C₆alkyl, and R⁷    is hydrogen or C₁-C₆alkyl are preferred, wherein radicals of the    formula

wherein R¹ and R² are independently of each other hydrogen, chloro,bromo, C₁-C₄alkyl, C₁-C₆alkoxy, C₁-C₆alkylamino, phenyl or CN,

-   G is —O—, —NR⁷—, —N═N— or —SO₂—,-   R³ and R⁴ are hydrogen, and-   R⁷ is hydrogen, methyl or ethyl are further preferred and    diketopyrrolopyrrole analogues, wherein A¹ and A² are radicals of    the formula

wherein R¹ and R² are independently of each other hydrogen, methyl,tert-butyl, chloro, bromo, phenyl or CN are particularly preferred forthe preparation of inks, colorants, pigmented plastics for coatings,non-impact-printing material, color filters, cosmetics, polymeric inkparticles, toners.

In the case of electroluminescence applications the following residuesare preferred for A¹ and A²:

wherein R²¹, R²², R²³, R²⁵ and R²⁶ are independently of each otherhydrogen, C₁-C₈alkyl, a hydroxyl group, a mercapto group, C₁-C₈alkoxy,C₁-C₈alkylthio, halogen, halo-C₁-C₈alkyl, a cyano group, an aldehydegroup, a ketone group, a carboxyl group, an ester group, a carbamoylgroup, an amino group, a nitro group, a silyl group or a siloxanyl groupand R²⁴ is a C₁-C₆alkyl group. Preferably R²¹, R²², R²³, R²⁵ and R²⁶ areindependently of each other hydrogen, C₁-C₈alkyl, C₁-C₈alkoxy orC₁-C₈alkylthio, wherein the following residues are particularlypreferred:

The residue A³ is in general selected from hydrogen, C₁-C₁₈alkyl,cyanomethyl, Ar³, —CR³⁰R³¹—(CH₂)_(m)—Ar³ or Y—R³², wherein R³⁰ and R³¹independently of each other stand for hydrogen or C₁-C₄alkyl, or phenylwhich can be substituted up to three times with C₁-C₃alkyl, Ar³ standsfor aryl, in particular phenyl or 1- or 2-naphthyl, C⁵-C₈cycloalkyl,such as cyclopentyl, cyclohexyl, cyclohoptyl and cyclooctyl, inparticular cyclohexyl, C₅-C₈cycloalkenyl, in particular cyclopentenyl,cyclopentadienyl and cyclohexenyl, or heteroaryl, which can besubstituted one to three times with C₁-C₈alkyl, C₁-C₈alkoxy, halogen orphenyl, which can be substituted with C₁-C₈alkyl or C₁-C₈alkoxy one tothree times, and m stands for 0, 1, 2, 3 or 4, Y is —C(O)—, —C(O)O—,—C(O)NH—, —SO₂NH— or —SO₂— and R³² is C₁-C₁₈alkyl, Ar³, or aralkyl.

A³ is preferably hydrogen, C₁-C₈alkyl such as methyl, ethyl, n-propyl,isopropyl, n-butyl, sec.-butyl, isobutyl, tert.-butyl, n-pentyl,2-pentyl, 3-pentyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl,1,1,3,3-tetiamethylbutyl and 2-ethylhexyl, Y—R³² wherein Y is —C(O)— andR³² is

wherein R⁴⁰ is C₁-C₄alkyl, —O—C₁-C₄alkyl, or —S—C₁-C₄alkyl and—(CH₂)_(m)—Ar wherein m is 1 and Ar is a group of the formula

which can be substituted one to three times with C₁-C₈alkyl,C₁-C₈alkoxy, halogen or phenyl.

Examples of preferred residues Ar are

wherein R⁵⁰ and R⁵¹ are independently of each other methyl, ethyl,n-propyl, isopropyl, n-butyl, sec.-butyl, isobutyl, tert.-butyl,methoxy, ethoxy, isopropoxy, tert.-butoxy or chlorine.

The residue A⁴ is in general selected from C₁-C₁₈alkyl or Ar³, inparticular Ar³, wherein A⁴ is preferably

which can be substituted one to three times with C₁-C₈alkyl,C₁-C₈alkoxy, halogen or phenyl.

Moreover, the present invention relates to diketopyrrolopyrroleanalogues of the formula

wherein A¹, A² and A³ have the meanings as given above, with the provisothat 3,5,6-triphenyl-1H-furo[3,4c]pyrrol-1,4-(5H)-dion is excluded.

The diketopyrrolopyrrole analogues of the formula II are intermediatesin the process for the preparation of the diketopyrrolopyrroles of theformula I and can be used as crystal growth regulators, wherein the term“regulating the crystal growth” refers to controlling the synthesis ofpigment particles to have a suitable pigmentary size and/or a narrowparticle size distribution as well as directing the growth of thecrystals to generate particles of a specifically desired shape, such asplatelet, needle, cubic, leaflet, prismatic and other geometric formsand/or of a specifically desired rheology. Consequently, the bettercontrol of the crystal growth allows gaining samples with a narrowerparticle size distribution and/or a better crystal shape, or bothtogether. The effect can be influenced by the chemical structure of theorganic pigment, the selection of the reaction media and theconcentration and chemical structure of the inventive particle growthregulator.

Hence, a further aspect of the instant invention is directed to pigmentcompositions comprising a primary pigment and from about 0.1-20% of thediketopyrrolopyrrole analogue of the formula II (including3,5,6-triphenyl-1H-furo[3,4-c]pyrrole-1,4-(5H)-dione), based on primarypigment weight. Preferred concentrations range from 1.0 to 10.0%, byweight of primary pigment. Although DPPs are preferred as primarypigment, the use of diverse pigment moieties is likewise available wherethe respective pigments are color compatible. Examples of applicableorganic primary pigments are: anthraquinone, phthalocyanine, perinone,perylene, dioxazine, diketopyrrolopyrrole, thioindigo, isoindoline,isoindolinone, quinacridone, quinacridonequinone, flavanthrone,indanthrone, anthrapyrimidine or quinophthalone pigments, and solidsolutions comprising these pigments. Pigments having good heatresistance and high transparency are especially suitable. Preferredorganic pigments are quinacridones, phthalocyanines, anthraquinones,perylenes, diketopyrrolopyrroles, isoindolinones and indanthrones.

When the pigment compositions are prepared, the diketopyrrolopyrroleanalogues of the formula II can be added during the pigment synthesis,during the fine dispersion process, before or after a finishing processby methods well-known in the art.

The diketopyrrolopyrrole analogues of formula II are in particular usedas crystal growth regulator in a process for the direct preparation ofDPP compounds of the formula

wherein X¹ and X² independently of each other are an unsubstituted orsubstituted isocyclic or heterocyclic aromatic radical. Said processcomprises

-   (a) heating an appropriate molar ratio of a disuccinate with a    nitrile of the formula (II)    X¹—CN  (XI)    or of the formula (III)    X²—CN  (XII)    or with mixtures of said nitriles, in an organic solvent and in the    presence of a strong base, to form a product,-   (b) conditioning of the intermediate condensation product obtained    in step (a) in water or a mixture of water and a water-miscible    solvent, optionally in the presence of an inorganic acid to form the    compound of formula (X), and-   (c) optionally conditioning of the product obtained in step (b) in    an aprotic solvent, wherein a diketopyrrolopyrrole analogue of    formula II is added in the heating step (a), the conditioning    step (b) or (c).

Due to the presence of crystal growth regulors DPP particles exhibitinga higher opacity/hiding power than commercial pigments synthesizedwithout growth controllers are obtained.

Hence, the present invention relates also to pigment compositionscomprising

-   a) a 1,4-diketopyrrolo[3,4-c]pyrrole of the formula X; and-   b) an effective crystal growth directing amount of a compound of    formula II.

The particle growth regulator is present in an amount of between 0.1 and10 weight %, based on the weight of the diketopyrrolopyrrole. A moreuseful range of particle growth regulator is from 0.5% to 4%, Inparticular 0.5% to 2% by weight of the particle growth regulator.

The expressions “direct” or “directly”, when used herein to describe apreparatory process for a pigmentary product, means that the specificsurface area of the pigmentary product will be within the range whichmakes it suitable for use as a pigment with specific desired properties.In order for the 1,4-diketopyrrolo[3,4-c]pyrroles of formula (I) to besuitable for direct use as a pigment, the surface area of the reactionproduct should be at least 15 meters²/gram, for example in the range offrom about 15 to about 50 m²/gram, preferably from about 20 to 50m²/gram. The surface area can be measured by nitrogen absorption oranother suitable method.

The radicals X¹ and X² may be the same or different, but are preferablyidentical. X¹ and X² as isocyclic aromatic radicals are preferablymonocyclic to tetracyclic radicals, most preferably monocyclic orbicyclic radicals such as phenyl, diphenyl, naphthyl and the like.Heterocyclic aromatic radicals X¹ and X² are preferably monocyclic totricyclic radicals. These radicals may be entirely heterocyclic or maycontain a heterocyclic ring and one or more fused benzene rings, and thecyano group can be linked both to the heterocyclic and to the isocyclicmoiety respectively. Examples of heterocyclic aromatic radicals arepyridyl, pyrimidyl, pyrazinyl, triazinyl, furyl, pyrrolyl, thiophenyl,quinolyl, cumarinyl, benzfuranyl, benzimidazolyl, benzoxazolyl,dibenzfuranyl, benzothiophenyl, dibenzothiophenyl, indolyl, carbazolyl,pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, indazolyl,benzthiazolyl, pyridazinyl, cinnolyl, quinazolyl, quinoxalyl,phthalazinyl, phthalazindionyl, phthalamidyl, chromonyl,naphtholactamyl, quinolonyl, ortho-sulfobenzimidyl, maleinimidyl,naphtharidinyl, benzimidazolonyl, benzoxazolonyl, benzthiazolonyl,benzthiazothionyl, quinazolonyl, quinoxalonyl, phthalazonyl,dioxopyrimidinyl, pyridonyl, isoquinolonyl, isoquinolinyl, isothiazolyl,benzisoxazolyl, benzisothiazolyl, indazolonyl, acridonyl,quinazolindionyl, quinoxalindionyl, benzoxazindionyl, benzoxazinonyl andnaphthalimidyl. Both the isocyclic and the heterocyclic aromaticradicals may contain the customary non-watersolubilising substituentssuch as those described in U.S. Pat. No. 6,057,449.

Pyrrolo[3,4-c]pyrroles of the formula X, in which X¹ and X²independently of one another are a group of the formula

in which X³¹, X³² and X³³ independently of one another are hydrogen,halogen, C₁-C₂₄alkyl, C₁-C₆alkoxy, C₁-C₁₈alkylthio, C₁-C₁₈alkylamino,di(C₁-C₁₈alkyl)amino, —CN, —NO₂, phenyl, trifluoromethyl,C₅-C₆cycloalkyl, —C═N—(C₁-C₂₄alkyl),

imidazolyl, pyrazolyl, triazolyl, piperazinyl, pyrrolyl, oxazolyl,benzoxazolyl, benzothiazolyl, benzimidazolyl, morpholinyl, piperidinylor pyrrolidinyl,

-   T₂ is —CH₂—, —CH(CH₃)—, —C(CH₃)₂—, —CH═N—, —N═N—, —O—, —S—, —SO—,    —SO₂— or —NX₃₈—, X³⁴ and X³⁵ independently of one another are    hydrogen, halogen, C₁₋₆-alkyl, C₁₋₆-alkoxy or —CN, X³⁶ and X₃₇    independently of one another are hydrogen, halogen or C₁₋₆-alkyl and    X³⁸ is hydrogen or C₁-C₆-alkyl; are preferred and DPPs of the    formula X, in which X¹ and X² are independently of each other a    group of the formula

in which X³¹ and X³² independently of one another are hydrogen, methyl,tert-butyl, chlorine, bromine, CN or phenyl are especially preferred.

In particular, the starting materials employed are nitriles of theformula

wherein each of X²⁰, X²¹ and X²², independently of one another, ishydrogen, fluorine, chlorine, bromine, carbamoyl, cyano,trifluoromethyl, C₂₋₁₀-alkylcarbamoyl, C₁₋₁₀-alkyl, C₁₋₁₀-alkoxy,C₁₋₁₀-alkylmercapto, C₂₋₁₀-alkoxycarbonyl, C₂₋₁₀-alkanoylamino,C₁₋₁₀-monoalkylamino, C₁₋₂₀-dialkylamino, phenyl or phenoxy,phenylmercapto, phenoxycarbonyl, phenylcarbamoyl or benzoylamino, eachunsubstituted or substituted by halogen, C₁₋₄-alkyl or C₁₋₄alkoxy, withthe proviso that at least one of X²⁰, X²¹ or X²² is hydrogen.

Preferably, the starting materials employed are nitriles of the formulaXIa, wherein X²⁰ is hydrogen and both X₂₁ and X²² are hydrogen, or oneof X²¹ or X²² is chlorine, bromine, C₁₋₄-alkyl, cyano, C₁₋₄-alkoxy, oris phenyl, phenoxy, carbamoyl or C₁₋₄-alkylcarbamoyl, each unsubstitutedor substituted by chlorine or methyl, or is phenylcarbamoyl which isunsubstituted or substituted by chlorine, methyl or methoxy, and theother is hydrogen. In a further preferred embodiment of the presentprocess only one nitrile of formula (XI) or of formula (XII) is used.

A preferred embodiment of the present invention concerns a processwherein X¹ and X², each independently of the other, are phenyl or saidphenyl substituted by one or two chlorine atoms, by one or two methylgroups, by methoxy, by trifluoromethyl, by cyano, by methpxycarbonyl, bymethyl, by tert-butyl, by dimethylamino or by cyanophenyl; naphthyl,biphenylyl; pyridyl or said pyridyl substituted by amyloxy; furyl orthienyl, such as phenyl, 3-chlorophenyl, 4-chlorophenyl,3,5-dichlorophenyl, 4-methylphenyl, 4-methoxyphenyl,3-trifluoromethylphenyl, 4-trifluoromethylphenyl, 3-cyanophenyl,4-cyanophenyl, 4-methoxycarbonylphenyl, 4-methylphenyl,4-tert-butylphenyl, 4-dimethylaminophenyl, 4-(para-cyanophenyl)phenyl,1-naphthyl, 2-naphthyl, 4-biphenylyl, 2-pyridyl, 6-amyloxy-3-pyridyl,2-furyl or 2-thienyl.

The disuccinates include dialkyl, diaryl or monoalkyl-monoarylsuccinates. The dialkyl and diaryl succinates may also be asymmetrical.However, it is preferred to use symmetrical disuccinates, mostpreferably symmetrical dialkyl succinates, most preferably symmetricaldialkyl succinates. If a diaryl or monoaryl-monoalkyl succinate isemployed, aryl denotes preferably phenyl which is unsubstituted orsubstituted by halogen such as chlorine, C₁₋₆-alkyl such as ethyl,methyl, isopropyl or tert-butyl, or C₁₋₆-alkoxy such as methoxy orethoxy. The preferred meaning of aryl is unsubstituted phenyl. If adialkyl or monoalkyl-monoaryl succinate is employed, then alkyl may beunbranched or branched, preferably branched, and may contain preferably1 to 18, in particular 1 to 12, more particularly 1 to 8 and morepreferably 1 to 5, carbon atoms. Branched alkyl is preferably sec- ortert-alkyl, for example, isopropyl, sec-butyl, tert-butyl, tert-amyl andcyclohexyl.

Examples of disuccinates are dimethyl succinate, diethyl succinate,dipropyl succinate, dibutyl succinate, dipentyl succinate, dihexylsuccinate, diheptyl succinate, dioctyl succinate, diisopropyl succinate,di-sec-butyl succinate, di-tert-butyl succinate, di-tert-amyl succinate,di-[1,1-dimethylbutyl] succinate, di-[1,1,3,3-tetramethylbutyl]succinate, di-[1,1-dimethylpentyl] succinate, di-[1-methyl-ethylbutyl]succinate, di-[1,1-diethylpropyl] succinate, diphenyl succinate,di-[4-methylphenyl] succinate, di-[4-chlorophenyl] succinate,monoethyl-monophenyl succinate, and dicyclohexyl succinate. Mostpreferably, the starting disuccinate is diisopropyl succinate.

Typically, the nitrile and the disuccinate are used in stoichiometricproportions. It can be advantageous to use the nitrile to be reactedwith the disuccinate in more than only stoichiometric proportions. Thereaction of the disuccinate with the nitrile is carried out in anorganic solvent. Examples of suitable solvents are primary, secondary ortertiary alcohols containing 1 to 10 carbon atoms, for example,methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol,tert-butanol, n-pentanol, 2-methyl-2-butanol, 2-methyl-2-pentanol,3-methyl-3-pentanol, 2-methyl-2-hexanol, 3-ethyl-3-pentanol,2,4,4-trimethyl-2-pentanol, or glycols such as ethylene glycol ordiethylene glycol; and also ethers such as tetrahydrofuran or dioxan, orglycol ethers such as ethylene glycol methyl ether, ethylene glycolethyl ether, diethylene glycol monomethyl ether or diethylene glycolmonoethyl ether; as well as dipolar aprotic solvents such asacetonitrile, benzonitrile, dimethylformamide, N,N-dimethylacetamide,nitrobenzene, N-methylpyrrolidone; aliphatic or aromatic hydrocarbonssuch as benzene or benzene substituted by alkyl, alkoxy or halogen, forexample, toluene, xylene, anisole or chlorobenzene; or aromaticheterocyclic compounds such as pyridine, picoline or quinoline. Inaddition, it is also possible to use the nitrile of formula (XI) or(XII) simultaneously as solvent if it is liquid in the temperature rangein which the reaction takes place. Mixtures of the above solvents mayalso be used. It is convenient to use 5 to 20 parts be weight of solventper 1 part by weight of reactants.

The process according to the invention is carried out in the presence ofa strong base.

Suitable strong bases are in particular the alkali metals themselvessuch as lithium, sodium or potassium, or alkali metal amides such aslithium amide, sodium amide or potassium amide, or alkali metal hydridessuch as lithium, sodium or potassium hydride, or alkaline earth metalalcoholates or alkali metal alcoholates which are derived preferablyfrom primary, secondary or tertiary aliphatic alcohols containing from 1to 10 carbon atoms.

The preferred strong base is an alkali metal alcoholate, the alkalimetals being preferably sodium or potassium and the alcoholate beingpreferably derived from a secondary or tertiary alcohol, for example,sodium or potassium isopropylate, sodium or potassium sec-butylate,sodium or potassium tert-butylate and sodium or potassium tert-amylate.

The strong base is employed in an amount of preferably from about 0.1 toabout 10 moles, most preferably from about 1.9 to about 4.0 moles, basedon one mole of the disuccinate. Regulation in particle size of the1,4-diketopyrrolo[3,4-c]pyrroles of formula X relative to the particlesize of the unregulated form thereof becomes noticeable with theinclusion of as little as 0.1% of the particle growth regulator relativeto the weight of the DPP compound of the formula II. The level of theregulator can be as high as 10% by weight. The preferred range ofparticle growth regulator is from 0.5 to 4% by weight, the mostpreferred range is from 0.5% to 2% by weight.

A preferred embodiment is to charge the reaction vessel with the nitrileand the base and then adding the disuccinate in the range of thereaction temperature, which addition order has a particularlyadvantageous effect on the yield. It is also possible to add thedisuccinate and the nitrile simultaneously to the base.

In particular, when using disuccinates containing alkyl radicals andalcoholates which are derived from lower alcohols such as methanol,ethanol, n-propanol, isopropanol or tert-butanol, it may be necessary toremove the lower alcohol formed during the reaction from the reactionmedium continuously in order to obtain higher yields.

If an alcohol is used as solvent and an alcoholate as base, it may proveadvantageous to choose an alcohol and alcoholate having the same alkylmoieties. It may likewise be advantageous if, in addition, thedisuccinate also contains such alkyl groups.

The conditioning step a) is carried out in water containing 0.0-100.0%,preferably 20.0-50.0% of a water-miscible solvent, at a conditioningtemperature of 1° C. to the reflux temperature, preferably close toreflux temperature, optionally in the presence of an inorganic acid.

In general water-miscible solvents are selected from water-misciblealcohols, polyols, nitrites, organic acids, amides, esters, ethers,ketones, amines or a mixture of these solvents.

Especially suitable water-miscible solvents include alcohols, inparticular C₁₋₄-alkyl alcohols, such as methanol, ethanol, n- andisopranol, polyols, like glycols, such as ethylene glycol, diethyleneglycol, ethers, like glycol ethers, such as ethylene glycol methylether, ethylene glycol ethyl ether, diethylene glycol monomethyl etheror diethylene glycol monoethylether, tetrahydrofuran (THF) and dioxane,organic acids, like acetic acid, ketones, like acetone, amines, such asmono-, di- or trialkylamines, such as propylamine, isopropylamine,diethylamine, dipropylamine, diisopropylamine, triethylamine,tripropylamine, triisopropylamine, bis(1-methyl)propylamine,1,1-dimethylethylamine and 2-ethylhexylamine, aromatic amines, such asaniline, toluidine or phenylene diamine, and mixtures thereof.

Suitable inorganic acids are hydrochloric, sulphuric and phosphoricacid.

The conditioning step b) is carried out in an aprotic, water-misciblesolvent in the presence of 0.0-99.0% water or in nonmiscible solventswith high boiling point or mixtures thereof at a conditioningtemperature from 1° C. to the boiling point, most preferably 10-20° C.below the boiling point of the solvent.

Suitable aprotic, water-miscible solvents include acetonitrile,N-methyl-2-pyrrolidone (NMP), gamma-butyrolactone, dimethylsulfoxide(DMSO), N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF), andmixtures thereof. Nonmiscible solvents include diphenylether, such asDowtherm® E, nonmiscible alcohols, such as pentanol, hexanol andheptanol, nonmiscible aromatic solvents like toluene, xylene,o-dichlorobenzene, nonmiscible ketones, nonmiscible ethers and cyclicethers, nonmiscible amines and aromatic amines, nonmiscible amides andesters and mixtures thereof.

The particle growth regulator of formula II can be added in the heatingstep (a), the conditioning step (b) or the conditioning step (c).

The process is illustrated below in further detail on the basis ofpreferred embodiments:

Process A-1:

The synthesis of the DPPs of the formula X is done in the presence of0.1-20.0%, preferably 0.25-2.0% DPP analogue of the formula II, whereinthe DPP analogue is preferably added at the beginning or at the end ofthe DPP synthesis, just before the conditioning.

The conditioning is carried out in water containing 0.0-100.0%,preferably 20.0-50.0% of a water-miscible solvent, at a conditioningtemperature of 1° C. to the reflux temperature, preferably close toreflux temperature.

Process A-2:

The synthesis of the DPPs of the formula X is done in the presence of0.1-20.0%, preferably 0.25-2.0% of the DPP analogue of formula II,wherein the DPP analogue of formula II is added at the beginning or atthe end of the DPP synthesis, just before the first conditioning.

The first conditioning is carried out in water containing 0.0-100.0%,preferably 20.0-50.0% of a water-miscible solvent at a conditioningtemperature of 1° C. to the reflux temperature, preferably 0°-40° C.,optionally in the presence of 1.0-99.0%, preferably 5.0-20.0% inorganicacid.

The second conditioning is carried out in an aprotic, water-misciblesolvent in the presence of 0.0-99.0% water at a conditioning temperaturefrom 1° C. to the boiling point, most preferably 10-20° C. below theboiling point of the solvent or in a non-miscible solvent with a highboiling point at a conditioning temperature from room temperature to theboiling point, preferably 10-20° C. below the boiling point of thesolvent.

Process A-3:

The synthesis of the DPPs of formula X is done without the addition of acrystal growth regulator of formula II.

The first conditioning is carried out in water containing 0.0-100.0%,preferably 20.0-50.0% of a water-miscible solvent at a conditioningtemperature of 1° C. to the reflux temperature, preferably 1°-40° C.,optionally in the presence of 1.0-99.0%, preferably 5.0-20.0% inorganicacid.

The second conditioning is carried out in an aprotic, water-misciblesolvent in the presence of 0.0-99.0% water at a conditioning temperaturefrom 1° C. to the boiling point, most preferably 10-20° C. below theboiling point of the solvent or in a non-miscible solvent with a highboiling point at a conditioning temperature from room temperature to theboiling point, preferably 10-20° C. below the boiling point of thesolvent in the presence of 0.1-20.0%, preferably 0.25-2.0% of the DPPanalogue of formula II.

Diketopyrrolopyrrole analogues, wherein A¹ and A² are radicals of theformula

R¹ and R² are independently of each other hydrogen, halogen,C₁-C₁₈alkyl, C₁-C₁₈alkoxy, C₁-C₁₈alkylmercapto, C₁-C₁₈alkylamino,C₁-C₁₈alkoxyrarbonyl, C₁-C₁₈alkylaminocarbonyl, —CN, —NO₂,trifluoromethyl, C₅-C₈cycloalkyl, —C═N—(C₁-C₁₈alkyl), phenyl,

imidazolyl, pyrazolyl, triazolyl, piperazinyl, pyrrolyl, oxazolyl,benzoxazolyl, benzothiazolyl, benzimidazolyl, morpholinyl, piperidinylor pyrrolidinyl, —CONX⁵X⁶, —C(O)OX⁷ or —SO₂X⁹; wherein X⁵ and X⁶ arehydrogen, linear or branched C₁₋₁₀-alkyl, C₅₋₁₀-cycloalkyl orC₆₋₁₀-aryl, X⁷ is hydrogen, linear or branched C₁₋₁₀-alkyl,C₅₋₁₀-cycloalkyl or C₆₋₁₀-aryl, X⁹ is hydrogen, linear or branchedC₁₋₁₀-alkyl, C₅₋₁₀-cycloalkyl, C₇₋₁₀-aralkyl, C₆₋₁₀-aryl or —NX¹⁰X¹¹,wherein X¹⁰ and X¹¹ are hydrogen, linear or branched C₁₋₁₀-alkyl,C₇₋₁₀-aralkyl or C₆₋₁₀-aryl,

-   G is —CH₂—, —CH(CH₃)—, —C(CH₃)₂—, —CH═N—, —N═N—, —O—, —S—, —SO—,    —SO₂—, —CONH— or —NR₇—, R³ and R⁴ are independently of each other    hydrogen, halogen, C₁-C₆alkyl, C₁-C₁₈alkoxy or —CN, R⁵ and R⁵ are    independently of each other hydrogen, halogen or C₁-C₆alkyl, and R⁷    is is hydrogen or C₁-C₆alkyl are preferred, wherein radicals of the    formula

wherein R¹ and R² are independently of each other hydrogen, chloro,bromo, C₁-C₄alkyl, C₁-C₆alkoxy, C₁-C₆alkylamino, phenyl or CN, —CONX⁵X⁶,or —SO₂X⁹; wherein X⁵ and X⁶ are hydrogen, linear or branchedC₁₋₄-alkyl, X⁹ is hydrogen, linear or branched C₁₋₄-calkyl, C₇₋₁₀-aralkyl, C₆₋₁₀-aryl or —NX¹⁰X¹¹, wherein X¹⁰ and X¹¹ are hydrogen,linear or branched C₁₋₁₀-alkyl, C₇₋₁₀-aralkyl or C₆₋₁₀-aryl;

-   G is —O—, —NR⁷—, —N═N— or —SO₂—,-   R³ and R⁴ are hydrogen, and-   R⁷ is hydrogen, methyl or ethyl are further preferred and    diketopyrrolopyrrole analogues, wherein A¹ and A² are radicals of    the formula

wherein R¹ and R² are independently of each other hydrogen, C₁₋₄-alkyl,such as methyl or tert-butyl, halogen, such as chloro or bromo,C₁₋₄-alkoxy or C₁₋₄-thioalkyl, phenyl or CN or —SO₂X⁹, wherein X⁹ isC₁₋₄-alkyl, phenyl, benzyl or NX¹⁰X¹¹, wherein X¹⁰ and X¹¹ are hydrogen,C₁₋₄-alkyl, benzyl or phenyl are particularly preferred.

A³ is preferably hydrogen, C₁-C₈alkyl such as methyl, ethyl, n-propyl,isopropyl, n-butyl, sec.-butyl, isobutyl, tert.-butyl, n-pentyl,2-pentyl, 3-pentyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl,1,1,3,3-tetramethylbutyl and 2-ethylhexyl, Y—R³² wherein Y is —C(O)— andR³² is

wherein R⁴⁰ is C₁-C₄alkyl, —O—C₁-C₄alkyl, or —S—C₁-C₄alkyl and—(CH₂)_(m)—Ar wherein m is 1 and Ar is a group of the formula

which can be substituted one to three times with C₁-C₈alkyl,C₁-C₈alkoxy, halogen or phenyl.

C₁-C₁₈alkyl is typically linear or branched—where possible—and examplesof C₁-C₁₈alkyl are methyl, ethyl, n-propyl, isopropyl, n-butyl,sec.-butyl, isobutyl, tert.-butyl, n-pentyl, 2-pentyl, 3-pentyl,2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 1,1,3,3-tetramethylbutyland 2-ethylhexyl, n-nonyl, decyl, undecyl, dodecyl, tetradecyl,pentadecyl, hexadecyl, heptadecyl and octadecyl. C₁-C₈alkyl such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, sec.-butyl, isobutyl,tert.-butyl, n-pentyl, 2-pentyl, 3-pentyl, 2,2-dimethylpropyl, n-hexyl,n-heptyl, n-octyl, 1,1,3,3-tetramethylbutyl and 2-ethylhexyl ispreferred. C₁-C₄alkyl such as methyl, ethyl, n-propyl, isopropyl,n-butyl, sec.-butyl, isobutyl or tert.-butyl is particularly preferred.The term “C₂-C₁₈alkenyl group” means an unsaturated linear or branchedaliphatic hydrocarbon group containing one or more double bonds, inparticular C₂₋₈-alkenyl, such as vinyl, allyl, 2-propen-2-yl,2-buten-1-yl, 3-buten-1-yl, 1,3-butadien-2-yl, 2-penten-1-yl,3-penten-2-yl, 2-methyl-1-buten-3-yl, 2-methyl-3-buten-2-yl,3-methyl-2-buten-1-yl and 1,4-pentadien-3-yl. The term “C₂-C₁₈alkynylgroup” means an unsaturated aliphatic hydrocarbon group containing atriple bond, in particular C₂-C₈-alkynyl such as ethynyl, 1-propyn-1-yl,2-butyn-1-yl, 3-butyn-1-yl, 2-pentyn-1-yl and 3-pentyn-2-yl.

Examples of C₁-C₁₈alkoxy, which can be linear or branched, are methoxy,ethoxy, n-propoxy, isopropoxy, n-butoxy, sec.-butoxy, isobutoxy,tert.-butoxy, n-pentoxy, 2-pentoxy, 3-pentoxy, 2,2-dimethylpropoxy,n-hexoxy, n-heptoxy, n-octoxy, 1,1,3,3-tetramethylbutoxy and2-ethylhexoxy, wherein C₁-C₄alkoxy such as methoxy, ethoxy, n-propoxy,isopropbxy, n-butoxy, sec.-butoxy, isobutoxy and tert.-butoxy ispreferred. Examples of C₁-C₁₈alkylmercapto are the same groups asmentioned for the alkoxy groups, except that the oxygen atom of theether linkage is replaced by a sulphur atom. Examples and preferencesfor C₁-C₁₈alkyl in C₁-C₁₈alkylamino and C₁-C₁₈alkylaminocarbonyl are thesame as mentioned for C₁-C₁₈alkyl. Examples and preferences forC₁-C₁₈alkoxy in C₁-C₁₈alkoxycarbonyl are the same as mentioned forC₁-C₁₈alkoxy.

The term “aryl group” is typically C₆-C₂₄aryl, such as phenyl,1-naphthyl, 2-naphthyl, 4-biphenyl, phenanthryl, terphenyl, pyrenyl, 2-or 9-fluorenyl or anthracenyl, preferably C₆-C₁₂aryl such as phenyl,1-naphthyl, 2-naphthyl, 4-biphenyl, which may be unsubstituted orsubstituted.

The term “aralkyl group” is typically C₇-C₂₄aralkyl, such as benzyl,2-benzyl-2-propyl, β-phenylethyl, α,α-dimethylbenzyl, ω-phenylbutyl,ω,ω-dimethyl-ω-phenylbutyl, ω-phenyldodecyl, ω-phenyloctadecyl,ωphenyleicosyl or ω-phenyldocosyl, preferably C₇-C₁₈aralkyl such asbenzyl, 2-benzyl-2-propyl, β-phenylethyl, α,α-dimethylbenzyl,ω-phenylbutyl, ω,ω-dimethyl-ω-phenylbutyl, ω-phenyldodecyl orω-phenyloctadecyl, and particularly preferred C₇-C₁₂aralkyl such asbenzyl, 2-benzyl-2-propyl, β-phenyl-ethyl, α,α-dimethylbenzyl,ω-phenyl-butyl, or ω,ω-dimethyl-ω-phenyl-butyl, in which both thealiphatic hydrocarbon group and aromatic hydrocarbon group may beunsubstituted or substituted.

Examples of C₅-C₈cycloalkyl are cyclopentyl, cyclohexyl, cycloheptyl andcyclooctyl, which may be unsubstituted or substituted. The term“C₅-C₈cycloalkenyl group” means an unsaturated alicyclic hydrocarbongroup containing one or more double bonds, such as cyclopentenyl,cyclopentadienyl and cyclohexenyl, which may be unsubstituted orsubstituted.

The term “heteroaryl” is a ring with five to seven ring atoms, whereinnitrogen, oxygen or sulfur are the possible hetero atoms, and istypically an unsaturated heterocyclic radical with five to 18 atomshaving at least six conjugated π-electrons such as thienyl,benzo[b]thienyl, dibenzo[b,d]thienyl, thianthrenyl, furyl, furfuryl,2H-pyranyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl,phenoxythienyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, bipyridyl,triazinyl, pyrimidinyl, pyrazinyl, pyridazinyl, indolizinyl, isoindolyl,indolyl, indazolyl, purinyl, quinolizinyl, quinolyl, isoquinolyl,phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl,pteridinyl, carbazolyl, carbolinyl, benzotriazolyl, benzoxazolyl,phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl,isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl or phenoxazinyl.

Examples of a halogen atom are fluorine, chlorine, bromine and iodine.

If the above-mentioned substituents can be substituted, possiblesubstituents are C₁-C₈alkyl, a hydroxyl group, a mercapto group,C₁-C₈alkoxy, C₁-C₈alkylthio, halogen, halo-C₁-C₈alkyl, a cyano group, analdehyde group, a ketone group, a carboxyl group, an ester group, acarbamoyl group, an amino group, a nitro group, a silyl group or asiloxanyl group, The present invention relates also to the use of theinventive DPP analogues of the general formula I for the preparation of

-   inks for printing inks in printing processes, for flexographic    printing, screen printing, packaging printing, security ink    printing, intaglio printing or offset printing, for pre-press stages    and for textile printing, for office, home applications or graphics    applications, such as for paper goods, for example, for ballpoint    pens, felt tips, fiber tips, card, wood, (wood) stains, metal,    inking pads or inks for impact printing processes (with    impact-pressure ink ribbons), for the preparation of-   colorants for coating materials, for industrial or commercial use,    for textile decoration and industrial marking, for roller coatings    or powder coatings or for automotive finishes, for high-solids    (low-solvent), water-containing or metallic coating materials or for    pigmented formulations for aqueous paints, for the preparation of-   pigmented plastics for coatings, fibers, platters or mold carriers,    for the preparation of-   non-impact-printing material for digital printing, for the thermal    wax transfer printing process, the ink jet printing process or for    the thermal transfer printing process, and also for the preparation    of-   color filters, especially for visible light in the range from 400 to    700 nm, for liquid-crystal displays (LCDs) or charge combined    devices (CCDs) or for the preparation of-   cosmetics or for the preparation of-   polymeric Ink particles, toners, dye lasers, dry copy toners liquid    copy toners, or electrophotographic toners, and electroluminescent    devices.

Illustrative examples of suitable organic materials of high molecularweight which can be colored with the inventive fluorescent DPP analoguesof the general formula I are vinyl polymers, for example polystyrene,poly-α-methylstyrene, poly-p-methylstyrene, poly-p-hydroxystyrene,poly-p-hydroxyphenylstyrene, polymethyl methacrylate and polyacrylamideas well as the corresponding methacrylic compounds, poly(methyl)maleate, polyacrylonitrile, polymethacrylonitrile, polyvinyl chloride,polyvinyl fluoride, polyvinylidene chloride, polyvinylidene fluoride,polyvinyl acetate, polymethyl vinyl ether and polybutyl vinyl ether;polymers which are derived from maleinimide and/or maleic anhydride,such as copolymers of maleic anhydride with styrene;poly(vinyl)pyrrolidone; ABS; ASA; polyamides; polyimides;polyamidimides; polysulfones; polyether sulfones; polyphenylene oxides;polyurethanes; polyureas; polycarbonates; polyarylenes; polyarylenesulfides; polyepoxides; polyolefins such as polyethylene andpolypropylene; polyalkadienes; biopolymers and the derivatives thereofe.g. cellulose, cellulose ethers and esters such as ethylcellulose,nitrocellulose, cellulose acetate and cellulose butyrate, starch,chitin, chitosan, gelatin, zein; natural resins; synthetic resins suchas alkyd resins, acrylic resins, phenolic resins, epoxide resins,aminoformaldehyde resins such as urea/formaldehyde resins andmelamine/formaldehyde resin; vulcanized rubber; casein; silicone andsilicone resins; rubber, chlorinated rubber; and also polymers which areused, for example, as binders in paint systems, such as novolaks whichare derived from C₁-C₆-aldehydes such as formaldehyde and acetaldehydeand a binuclear or mononuclear, preferably mononuclear, phenol which, ifdesired, is substituted by one or two C₁-C₉alkyl groups, one or twohalogen atoms or one phenyl ring, such as o-, m- or p-cresol, xylene,p-tert.-butylphenol, o-, m- or p-nonylphenol, p-chlorophenol orp-phenylphenol, or a compound having more than one phenolic group suchas resorcinol, bis(4-hydroxyphenyl)methane or2,2-bis(4-hydroxyphenyl)propane; as well as suitable mixtures of saidmaterials.

Particularly preferred high molecular weight organic materials, inparticular for the preparation of a paint system, a printing ink or ink,are, for example, cellulose ethers and esters, e.g. ethylcellulose,nitrocellulose, cellulose acetate and cellulose butyrate, natural resinsor synthetic resins (polymerization or condensation resins) such asaminoplasts, in particular urea/formaldehyde and melamine/formaldehyderesins, alkyd resins, phenolic plastics, polycarbonates, polyolefins,polystyrene, polyvinyl chloride, polyamides, polyurethanes, polyester,ABS, ASA, polyphenylene oxides, vulcanized rubber, casein, silicone andsilicone resins as well as their possible mixtures with one another.

It is also possible to use high molecular weight organic materials indissolved form as film formers, for example boiled linseed oil,nitrocellulose, alkyd resins, phenolic resins, melamine/formaldehyde andurea/formaldehyde resins as well as acrylic resins.

Said high molecular weight organic materials may be obtained singly orin admixture, for example in the form of granules, plastic materials,melts or in the form of solutions, in particular for the preparation ofspinning solutions, paint systems, coating materials, inks or printinginks.

In a particularly preferred embodiment of this invention, the inventiveDPPs of the general formula I are used for the mass coloration ofpolyvinyl chloride, polyamides and, especially, polyolefins such aspolyethylene and polypropylene as well as for the preparation of paintsystems, including powder coatings, inks, printing inks, color filtersand coating colors. Illustrative examples of preferred binders for paintsystems are alkyd/melamine resin paints, acryvmelamine resin paints,cellulose acetate/cellulose butyrate paints and two-pack system lacquersbased on acrylic resins which are crosslinkable with polyisocyanate.

According to observations made to date, the inventive DPPs of thegeneral formula I can be added in any desired amount to the material tobe colored, depending on the end use requirements. In the case of highmolecular weight organic materials, for example, the fluorescent DPPanalogues of the general formula I prepared according to this inventioncan be used in an amount in the range from 0.01 to 50, preferably from0.01 to 5% by weight, based on the total weight of the colored highmolecular weight organic material.

Hence, another embodiment of the present invention relates to acomposition comprising

-   (a) 0.01 to 50, preferably 0.01 to 5, particularly preferred 0.01 to    2% by weight, based on the total weight of the colored high    molecular organic material, of a DPP of the general formula I    according to the present invention, and-   (b) 99.99 to 50, preferably 99.99 to 95, particularly preferred    99.99 to 98% by weight, based on the total weight of the colored    high molecular organic material, of a high molecular organic    material, and-   (c) if desired, customary additives such as rheology improvers,    dispersants, fillers, paint auxiliaries, siccatives, plasticizers,    UV-stabilizers, and/or additional pigments or corresponding    precursors in effective amounts, such as e.g. from 0 to 50% by    weight, based on the total weight of (a) and (b).

To obtain different shades, the inventive DPPs of the general formula Imay advantageously be used in admixture with fillers, transparent andopaque white, colored and/or black pigments as well as customary lusterpigments in the desired amount.

For the preparation of paint systems, coating materials, color filters,inks and printing inks, the corresponding high molecular weight organicmaterials, such as binders, synthetic resin dispersions etc. and theinventive DPPs of the general formula I are usually dispersed ordissolved together, if desired together with customary additives such asdispersants, fillers, paint auxiliaries, siccatives, plasticizers and/oradditional pigments or pigment precursors, in a common solvent ormixture of solvents. This can be achieved by dispersing or dissolvingthe individual components by themselves, or also several componentstogether, and only then bringing all components together, or by addingeverything together at once. Hence, a further embodiment of the presentinvention relates to a method of using the inventive DPPs of the generalformula I for the preparation of dispersions and the correspondingdispersions, and paint systems, coating materials, color filters, inksand printing inks comprising the inventive DPPs of the general formulaI.

A particularly preferred embodiment relates to the use of the inventivefluorescent DPPs of the general formula I for the preparation offluorescent tracers for e.g. leak detection of fluids such aslubricants, cooling systems etc., as well as to fluorescent tracers orlubricants comprising the inventive DPPs of the general formula I.Usually, such lubricant compositions, e.g. for a refrigerant, comprisean oil selected from the group consisting of naphthalenic oils,paraffinic oils, alkylated benzene oils, polyalkyl silicate oils,polyglycols, esters, polyether polyols, polyvinyl ethers,polycarbonates, fluorinated silicones, perfluoroethers, aromaticcompounds with fluoroalkyloxy or fluoroalkylthio substituents. Theamount of the inventive DPP of the general formula I in the lubricant ischosen generally in an amount of from 100 to 1000 ppm. If the inventivecompound I is water-soluble, it could be used as tracer in water aswell.

A particular embodiment of this invention concerns ink jet inkscomprising the inventive DPPs of the general formula I.

For the coloring of high molecular weight organic material, theinventive DPPs of the general formula I, optionally in the form ofmasterbatches, usually are mixed with the high molecular weight organicmaterials using roll mills, mixing apparatus or grinding apparatus.Generally, the pigmented material is subsequently brought into thedesired final form by conventional processes, such as calandering,compression molding, extrusion, spreading, casting or injection molding.In order to prepare non-rigid moldings or to reduce their brittleness itis often desired to incorporate so-called plasticizers into the highmolecular weight organic materials prior to forming. Examples ofcompounds which can be used as such plasticizers are esters ofphosphoric acid, phthalic acid or sebacic acid. The plasticizers can beadded before or after the incorporation of the inventive DPP analoguesof the general formula I into the polymers. It is also possible, inorder to achieve different hues, to add fillers or other coloringconstituents such as white, color or black pigments in desired amountsto the high molecular weight organic materials in addition to theinventive DPP analogues of the general formula I.

For colouring lacquers, coating materials and printing inks the highmolecular weight organic materials and the inventive DPPs of the generalformula I, alone or together with additives, such as fillers, otherpigments, siccatives or plasticizers, are generally dissolved ordispersed in a common organic solvent or solvent mixture. In this caseit is possible to adopt a procedure whereby the individual componentsare dispersed or dissolved individually or else two or more aredispersed or dissolved together and only then are all of the componentscombined.

The present invention additionally relates to inks comprising acoloristically effective amount of the inventive DPP of the generalformula I.

Processes for producing inks especially for ink jet printing aregenerally known and are described for example in U.S. Pat. No.5,106,412.

When mixing a DPP of the general formula I with polymeric dispersants itis preferred to use a water-dilutable organic solvent.

The weight ratio of the pigment dispersion to the ink in general ischosen in the range of from 0.001 to 75% by weight, preferably from 0.01to 50% by weight, based on the overall weight of the ink.

The preparation and use of color filters or color-pigmented highmolecular weight organic materials are well-known in the art anddescribed e.g. in Displays 14/2, 1151 (1993), EP-A-784085, orGB-A-2,310,072.

The color filters can be coated for example using inks, especiallyprinting inks, which can comprise the inventive DPPs of the generalformula I or can be prepared for example by mixing a DPP of the generalformula I with chemically, thermally or photolytically structurable highmolecular weight organic material (so-called resist). The subsequentpreparation can be carried out, for example, in analogy to EP-A-654 711by application to a substrate, such as a LCD, subsequentphotostructuring and development.

The present invention relates, moreover, to toners comprising a DPP ofthe general formula I or a high molecular weight organic materialcoloured with a DPP of the general formula I in a coloristicallyeffective amount.

In a particular embodiment of the process of the invention, toners,coating materials, inks or colored plastics are prepared by processingmasterbatches of toners, coating materials, inks or colored plastics inroll mills, mixing apparatus or grinding apparatus.

The present invention additionally relates to colorants, coloredplastics, polymeric ink particles, or non-Impact-printing materialcomprising an inventive DPP of the general formula I or a high molecularweight organic material coloured with a DPP of the general formula I ina coloristically effective amount.

A coloristically effective amount of the pigment dispersion according tothis invention comprising an inventive DPP I denotes in general from0.0001 to 99.99% by weight, preferably from 0.001 to 50% by weight and,with particular preference, from 0.01 to 5% by weight, based on theoverall weight of the material pigmented therewith.

Further, the inventive compounds I can be used for textile applicationand for the dying of paper.

The following examples illustrate various embodiments of the invention,but the scope of the invention is not limited thereto.

EXAMPLES Example 1

Compound 5:

To pre-dried t-amyl alcohol (40 ml) was added sodium (1.50 g, 0.0652mol) with stirring under nitrogen and the mixture heated to reflux(105-110° C.) until all the sodium dissolved. The solution was cooled to25° C., then the lactam ester 9 (5.03 g, 0.0218 mol) and ethyl benzoate(3.27 g, 0.0218 mol) were added. The mixture was then heated to refluxfor 5.5 h during which time an orange solution developed. The cooledmixture was added to an ice-cooled mixture of methanol (10 ml) and water(50 ml), acidified dropwise with concentrated hydrochloric acid (3 ml)then extracted with tetrahydrofuran/diethyl ether, dried (Na₂SO₄) andconcentrated. Recrystallisation from aqueous ethanol yielded ambercoloured crystals.

Yield 2.38 g (33%), m.p. 156-157° C. (Found: C, 71.5; H, 5.2; N, 4.2.C₂₀H₁₇NO₄ requires C, 71.6; H, 5.1; N, 4.2%). δ_(H) 0.67 (3H, t, J 7.2,OCH₂CH₃), 3.56 (2H, q, OCH₂CH₃), 7.40-7.56 (6H, m, m-lp-Ar—H), 7.62-7.68(4H, m, o-Ar—H), 9.52 (1H, br. s, NH). m/z 335 (M⁺, 54%), 289 (100), 105(56).

Compound 6:

A mixture of compound 5 (10 g, 0.0299 mol) and Dowtherm A (200 ml) washeated to 230-240° C. under nitrogen for 64 h. The solution was thencooled to 25° C. and added dropwise to petrol ether 40-60 (300 ml) uponwhich a fluorescent orange solid precipitated. This was filtered off,washed with further hexane and dried in vacua. Yield 3.48 g (40%).(Found: C, 74.9; H, 4.2; N, 4.8%. C₁₈H₁₁NO₃ requires C, 74.7; H, 3.8; N,4.8). m/z289 (M⁺, 100%), 204 (20), 105 (35), 77 (35).

Compound 7:

To a suspension of sodium hydride (0.20 g, 55-65% dispersion in mineraloil) in tetrahydroturan (100 ml) was added compound 6 under nitrogen at25° C. (1.0 g, 0.0034 mol) and the mixture was heated briefly to refluxduring 5 mins. The solution was cooled to 25° C., then benzyl bromide(0.70 g, 0.0041 mol) was added. The solution was heated to reflux during19 h, then cooled. Water (50 ml) was added and the mixture extractedwith a tetrahydrofuran/ethyl acetate solvent mixture. The organicextracts were concentrated and the residue mixed with petrol ether 40-60and treated in an ultrasonic bath for 20 mins. The product was filteredoff and dried in vacua. Yield 0.97 g (74%). (Found: C, 78.8; H, 4.9; N,3.6%. C₂₅H₁₇NO₃ requires C, 79.1; H, 4.5; N, 3.7). m/z379 (M₊, 35%), 105(50), 91 (100), 77 (20).

Compound 8:

A mixture of compound 7 (10 g, 0.0264 mol),N,N′-dicyclohexylcarbodiimide (13.5 g, 0.0655 mol), dichloromethane (300ml), trifluoroacetic acid (3 drops) and aniline (5 g, 0.0538 mol) wasstirred under nitrogen for 16 h at 40° C. Further aniline (15 g, 0.1613mol) and N,N′-dicyclohexylcarbodiimide (10 g, 0.0485 mol) were added andheating continued for 24 h. The mixture was then concentrated. Theresidue was recrystallised from 1,4-dioxan then washed with hotisopropyl alcohol, methanol and water then dried in vacuo. Fluorescentorange solid, yield 1.87 g, (16%). (Found: C, 81.2; H, 5.3; N, 6.4%.C₃₁H₂₂N₂O₂ requires C, 81.9; H, 4.9; N, 6.2). m/z 454 (M⁺, 100%).

Example 2

Compound 11:

To pre-dried t-amyl alcohol (230 ml) was added sodium (6.82 g, 0.2967mol) with stirring under nitrogen and the mixture heated to reflux(105-110° C.) until all the sodium dissolved. The solution was cooled to70° C. and then the lactam ester 10 (26.29 g, 0.0989 mol) and ethyl4-chlorobenzoate (18.27 g, 0.0990 mol) were added. The mixture was thenheated to reflux for 22 h during which time an orange solutiondeveloped. The mixture was then cooled and acidified with 10%hydrochloric acid (250 ml), then extracted with tetrahydrofuran/ethylacetate, the organic extracts washed with water and then concentrated.The solid residue was recrystallised from anethanol/isopropylalcohol/water mixed solvent system to a yield beigecoloured crystals which were filtered off and dried in vacuo. Yield31.36 g (78%). Found: C, 59.4; H, 4.1; N, 3.7; Cl, 17.4%. C₂₀H₁₅Cl₁₂O₄Nrequires C, 59.4; H, 3.7; N,3.5; Cl, 17.5).

Compound 12:

A mixture of compound 11 (15.0 g, 0.0371 mol) and Dowtherm A (300 ml)was heated to 205-210° C. during 48 h then cooled. The mixture was thenadded dropwise to petrol ether 40-60 (1 l) and the fluorescent purplewas filtered off, washed with further petrol and dried in vacuo. Yield8.95 g (68%). (Found: C, 60.4; H, 2.8; N, 3.9%. C₁₈H₈Cl₂NO₃ requires C,60.5; H, 2.3; N, 3.9). m/z357 (M⁺, 100%), 139 (100), 111 (85), 75 (35).

Example 3

Compound 13

To a mixture of intermediate 6 (0.99 g, 0.0034 mol) and tetrahydrofuran(200 ml) under nitrogen at 25° C. was added sodium hydride (0.16 g,55-65% mineral oil dispersion). The mixture was heated briefly during 5mins. to reflux, during which time gas was evolved. The mixture was thencooled to 25° C. and methyl iodide (1.46 g, 0.0103 mol) was added. Thesolution was stirred at 25° C. during 16 h. Water (100 ml) was thenadded and the mixture extracted with a tetrahydrofuran/ethyl acetatemixed solvent. The combined organic extracts were then concentrated,redissolved in DMSO (20 ml) and added dropwise to water (200 ml). Thefluorescent orange precipitate was filtered off, washed with water anddried in vacuo. Yield 0.96 g (93%). (Found C, 75.2; H, 4.5; N, 4.6%.C₁₉H₁₃NO₃ requires C, 75.2; H, 4.3; N, 4.6).

Example 4

Compound 14

A mixture of intermediate 6 (0.74 g, 0.0026 mol), di-t-butyl dicarbonate(1.34 g, 0.0061 mol), 4-(N,N′)-dimethylaminopyridine (0.05 g, 0.0004mol) and tetrahydrofuran (100 ml) was stirred at 25° C. under nitrogenfor 24 h. The reaction mixture was concentrated, then the residue wasmixed with methanol (10 ml) and the solid precipitate was filtered off,washed with methanol (5 ml) and dried in vacuo. Fluorescent yellowsolid, yield 0.97 g (96%).

Example 5

1.0 g of the DPP analogue 8 was mixed with 63.0 g of polyvinyl chloride,3.0 g of epoxidized soya oil, 2.0 g of barium/cadmium thermal stabilizerand 32.0 g of dioctyl phthalate, and the mixture was processed on aroller mill at 160° C. for 8 minutes to give a thin sheet. The PVC sheetthus produced is characterized by its very strong fluorescentyellow-orange color.

Example 6

In a 200 ml 4-neck flat bottom reactor equipped with a glass stirrer, athermometer, a nitrogen inlet tube, a bubble counter and an additionfunnel 60.0 g t-amylalcohol techn. and 5.24 g solid sodium were poured.It was heated to 130° C. ext. temperature (int. temp. 110° C.) and asmall amount of iron(III) trichloride was added. After the solid sodiumhas completely disappeared, a mixture of 14.90 g p-chlorobenzonitrile,14.27 g diisopropylsuccinimide and 42.70 g t-amylalcohol was addedwithin 2 hours. The temperature was decreased to 85° C. (int.) and thereaction mixture was stirred for 2 hrs. The temperature is thendecreased to 40° C. and 0.32 g of compound 6 described in example 1 wereadded. The reaction mixture was then transferred within 15 min. inanother reactor, poured into a mixture of 275 ml demineralised water,275 ml methanol and 120 ml sulphuric acid at 40° C. The pigment wasconditioned during 18 hrs. After filtration and drying the obtained darkred pigment powder was poured into 300 ml dimethylacetamide and furtherconditioned for 5 hrs at 140° C. 13.70 g (71%) of a bright red pigmentwhich in comparison to the pigment of comparative example 1 exhibits apurer, brighter and yellower shade in mass tone, along with a higheropacity. The gloss at 20° C. was slightly better than DPP Red BO. Inwhite reduction, the pigment showed equal colour strength. In whitereduction 5:95, the weather stability (2000 h WOM) was comparable to DPPRed BO.

Test Method:

4.0 g untreated pigment were added to 46.0 g AM-paint prepared asdescribed below. The paint at 8% pigment conc. was dispersed 1 hr. inSkandex with 200 g glass beads having a diameter of 2 mm. The dispersedpaint is drawn down (100 μm) on a Mylar sheet and poured on a glassplate. After 10 minutes, the Mylar sheet and the glass plate wereallowed to dry 30 minutes at 130° C. in a hot air oven. The Mylar sheethad the following colour properties (Datacolor 3890 calorimeter):lightness L*, chroma C*, hue h and opacity (as ΔTr. over black). Thecontrast paper was a clean and new standard Leneta. From the poured outglass plates the gloss at 20° angle using a gloss meter ZGM 20° fromZehntner Electronics Co. (Switzerland) was determined.

A white reduction containing 5 parts of pigment and 95 parts of whitepigment was also prepared: 3.27 g of the previously prepared mass tonepaint were added to 26.73 g white AM-paint (description below) and mixedwith a simple glass stirrer to yield 30 g white reduction, which isdrawn down on a Mylar sheet (100 μm). From the Mylar sheet the colourstrength was assessed.

Preparation of the AM-paint

Mass tone: 60.00 parts by weight Bayer Alkydal F 310, 60% in solventnaphtol 16.00 parts by weight Cytec Cymel 327, 90% in isobutanol 19.00parts by weight xylol  2.00 parts by weight butanol  2.00 parts byweight 1-methoxy-2-propanol  1.00 parts by weight silicone oil A, 1% inxylol White 20.00 parts by weight titanium dioxide Kronos 2310reduction: 47.67 parts by weight Bayer Alkydal F 310, 60% in solventnaphtol 12.75 parts by weight Cytec Cymel 327, 90% in butanol  0.50parts by weight Aerosil 200  1.59 parts by weight 1-methoxy-2-propanol 1.59 parts by weight butanol 15.10 parts by weight xylol  0.80 parts byweight silicone oil A, 1% in xylol

Comparative Example 1

Example 6 was repeated except that no compound 6 was added. Afterfiltration and drying in an oven under vacuum 16.03 g (83%) bright redpigment exhibiting colour properties comparable to the‘state-of-the-art’ (commercial DPP Red BO) were obtained. The weatherstability of this pigment is also comparable to the ‘state-of-the-art’(2000 hrs WOM, white reduction 5:95).

1. A process for the preparation of diketopyrrolopyrroles of the formula

comprising the steps of: reacting a compound of the formula

with a compound ofA³-X  (V), wherein A¹ and A² are C₁-C₁₈alkyl, C₂-C₁₈alkenyl,C₂-C₁₈alkynyl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl, aryl or heteroaryl,A³ is hydrogen, C₁-C₁₈alkyl, cyanomethyl, Ar³, —CR³⁰R³¹—(CH₂)_(m)—Ar³ orY—R³², wherein R³⁰ and R³¹ independently of each other stand forhydrogen or C₁-C₄alkyl, or phenyl which can be substituted up to threetimes with C₁-C₃alkyl, Ar³ stands for aryl, C₅-C₈cycloalkyl,C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to threetimes with C₁-C₈alkyl, C₁-C₈alkoxy, halogen or phenyl, which can besubstituted with C₁-C₈alkyl or C₁-C₈alkoxy one to three times, and mstands for 0, 1, 2, 3 or 4, Y is —C(O)—, —C(O)O—, —C(O)NH—, —SO₂NH— or—SO₂— and R³² is C₁-C₁₈alkyl, Ar³, or aralkyl, and A⁴ is C₁-C₁₈alkyl orAr³ where X is a leaving group, to give a compound of the formula

and ii) reacting the compound of formula (II) with a primary amine ofthe formulaA⁴—NH₂   (III).
 2. The process according to claim 1, wherein thecompound of the formula IV is obtained by heating a compound of theformula

in an inert solvent, wherein A¹ and A² have the meanings as given inclaim 1 and R is C₁-C₁₈alkyl, aryl, or aralkyl, which can be substitutedone to three times with C₁-C₈alkyl, C₁-C₈alkoxy, or halogen.